Extraction of accurate 3-D ground coordinates from interferometric radar altimeter (IRA)

Conventional radar altimeter system can accurately measure the sea level within several centimeters, whereas it is difficult to precisely estimate the three-dimensional ground coordinates because the ground surface is very rough. To overcome the drawback of the pulse-limited altimeter, we have developed and validated the processing algorithm which is combined with new synthetic aperture and interferometric signal processing. The proposed algorithm can accurately measure the three-dimensional ground coordinates. In a set of 70 simulations, the averages of errors in X, Y and Z directions were about -0.40 m, -0.02 m and 4.22 m, respectively and the standard deviations of errors were about 3.4 m, 0.3 m and 4.6 m, respectively. The overall results demonstrate that the proposed algorithm is effective for accurate three-dimensional geopositioning.